Arctic Field Projects

Project Title: Collaborative Research: GreenTrACS: a Greenland Traverse for Accumulation and Climate Studies (Award# 1417678)

PI: Osterberg, Erich Christian (
Phone: (603) 646.1096 
Institute/Department: Dartmouth College, Department of Earth Sciences 
IPY Project?
Funding Agency: US\Federal\NSF\GEO\OPP\ARC\ANS
Program Manager: Dr. Marc Stieglitz ( )
Discipline(s): | Cryosphere\Glaciology | Cryosphere\Ice Geochemistry | Cryosphere\Ice Penetrating Radar | Cryosphere\Ice Sheet Mass Balance |

Project Web Site(s):

Science Summary:
The investigators plan a traverse in the Western Greenland percolation zone over two field seasons to develop continuous in-situ snow accumulation and firn density records using ground-based radar and shallow firn cores. The research objectives include: (1) determining the patterns, in time and space, of snow accumulation in Western Greenland over the past 20-40 years; (2) evaluating surface melt refreeze and englacial meltwater storage in the Western Greenland percolation zone over the past 20-40 years; and (3) quantifying the accumulation and surface melt biases of the most recent climate reanalysis models and their regional climate model counterparts. This project intends to advance knowledge and understanding by providing in-situ validation observations for both the mass gain (snow accumulation) and mass loss (surface melt) components of Western Greenland surface mass balance. Previous studies have shown that the western edge of the Greenland Ice Sheet has been losing mass at an accelerating rate since 2005, due mostly to decreasing surface mass balance. However, surface mass balance trends derived from regional climate models differ by a factor of ~2.5 in this region. Western Greenland firn core accumulation records, required for model validation, generally end in 1996-1998, before the most recent period of accelerated mass loss. The investigators will develop continuous records of Western Greenland snow accumulation over the last 20-40 years using ground-penetrating radar validated by frequent snow pits and firn cores (25-30 m) analyzed for chemistry. They will also use a multi-offset radar method to calculate firn density continuously along the traverse, providing a means to assess past surface melt, refreeze and current meltwater storage in glacier aquifers, as well as critical density-profile data for air- and spaceborne remote sensing work. Meltwater refreeze shows the largest variability in regional climate models among surface mass balance components, and thus validation observations are critically needed. The traverse route will crisscross the percolation zone, near-parallel to the steepest accumulation and surface melt gradients, which will increase the value of the dataset for model validation. The traverse will overlap previous traverse routes, IceBridge airborne radar flight paths, and reoccupy previously sampled sites to update firn core accumulation records by 18-20 years. In addition, the project will collect cores from new sites in data-poor regions at lower elevations, where both accumulation and surface melt increase and regional climate model validation is most needed. Surface mass balance validation of several climate reanalysis models will lead to more accurate assessments of current and future Greenland Ice Sheet mass balance trends, which is critical for accurately predicting future sea-level rise.

Logistics Summary:
This project, Greenland Traverse for Accumulation and Climate Studies (GreenTrACS), is a collaboration between Osterberg and Hawley (1417678, Dartmouth, LEAD), Birkel (1417640, U of Maine), and Marshall (1417921, Boise State). In 2016 a team of five will conduct a sampling traverse in Greenland during spring/early summer, April to mid-June. They will fly to Kangerlussuaq via the Air National Guard (ANG) logistics chain and spend several days preparing before flying on to Raven Camp, the traverse starting point, via the ANG. After departing several days later, the team will spend about a month on a snowmachine-based traverse of about 1700 km. They will tent camp for the duration, collecting ice cores (which they will cache along the traverse in several locations) and performing ground-based radar measurements en route. After reaching the traverse end point, Summit Station, the group will fly back to Kangerlussuaq via the ANG, pack up, and then depart Greenland via the ANG. The cached ice cores will be retrieved by Twin Otter immediately following the expedition, and kept in frozen storage until they can be transported to the U.S. on a “cold-deck” ANG flight. CPS staff will unload the cores in New York and a freezer truck from Dartmouth will meet the aircraft to deliver them to the home institution. In 2017, a team of five will travel to Kangerlussuaq via the Air National Guard and then on to Summit Station. The researchers will base out of Summit, traversing via snow machine, conducting similar field work to 2016 for a duration of just under two months. After returning to Summit, they will fly the ANG back to Kangerlussuaq and the US. There will be a crew swap mid-May with one person leaving and the co-PI joining the team in the field.

CPS will provide ANG coordination for passengers and cargo, frozen core sample transport to Kangerlussuaq, sample transport to NY via ANG annual ‘cold deck’, freezer space in Kangerlussuaq between flights, KISS and Summit user days, fixed wing charters, ice core boxes, equipment fuel, sleds, generators, camping equipment, safety gear, med kit/ service and communications equipment. All other support will be arranged and paid for by the grant.
SeasonField SiteDate InDate Out#People
2016Greenland - Kangerlussuaq04 / 25 / 2016 06 / 11 / 20165
2016Greenland - Raven04 / 30 / 2016 05 / 02 / 20165
2016Greenland - Summit06 / 06 / 2016 06 / 09 / 20165
2017Greenland - Kangerlussuaq04 / 18 / 2017 06 / 29 / 20176
2017Greenland - Summit05 / 01 / 2017 06 / 25 / 20176

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